A multicast stream corresponds with transmission of content to two or more devices. A multicast transmission may be characterized as a one-to-many transmission whereby two or more devices desiring access to a multicast stream may commonly access a port or frequency associated with a sourcing device. Some systems may be configured to facilitate on-demand transmission of multicast streams such that multicast streams are constructed and deconstructed according to a number of accessing devices. In particular, such systems may be configured to construct multicast streams only when requested by at least one device and to deconstruct any multicast stream which is not actively being accessed by at least one device. The multicast streams may be configured to facilitate transmission of various types of content, including video, audio and data. In some cases the content may be linear content, such as but not necessarily limited to that sourced from a continuous stream of signaling, which may be carried over Internet protocol (IP). The IP-based transmission may allow the multicast streams to be packetized for delivery over the Internet or other data network.